Minor perf improvement to queryEntities when limit=0

Updates queryEntities to not execute dbQuery at all when limit is 0

Signed-off-by: Brian Hudson <brian.r.hudson@gmail.com>

.changeset/ninety-rules-sneeze.md

@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-catalog-backend': patch
+---
+
+Minor performance improvement for queryEntities when the limit is 0.

plugins/catalog-backend/src/service/DefaultEntitiesCatalog.ts

@@ -451,7 +451,7 @@ export class DefaultEntitiesCatalog implements EntitiesCatalog {
     countQuery.count('search.entity_id', { as: 'count' });
 
     const [rows, [{ count }]] = await Promise.all([
-      dbQuery,
+      limit > 0 ? dbQuery : [],
       // for performance reasons we invoke the countQuery
       // only on the first request.
       // The result is then embedded into the cursor